Overload circuit breaker



Dec. 11, 1945. c. w. KUHN OVERLOAD CIRCUIT BREAKER Filed Oct. 27, 1943 to lock said annular member to said supporting member subject to release upon melting of said solder film, such restraining device having a current conducting path axially through said annular member for heating said solder film and melting the same under given current conditions, said conducting path having uniformity of conductivity from terminal to terminal and having surroundings minimizing danger of hot spots therein in the event of maximum overload.

5. A thermal restraining device for electric switches and other devices, comprising a high resistance core member having from terminal to terminal a thin surrounding covering intimately bonded thereto, afiording insulation thereof and also affording a surface to which solder willbond, a sleeve surrounding said core member with relatively small clearance therefrom, and a thin film of solder bonding said sleeve to said core member subject to release upon melting of said solder, said core member being of uniform conductivity from terminal to terminal and having surroundings minimizing danger of hot spots therein.

6. A thermal restraining device for electric switches and the like comprising a core member of resistance material having at opposite ends a terminal supporting the same against rotation and having extending from terminal to terminal a thin surrounding covering intimately bonded therewith and comprising an inner layer of insulation and an outer layer of material with which solder will bond, such layers being intimately bonded, a thin film of solder bonded to said outer layer and a sleeve surrounding said solder film which is locked to said core member by said solder film subject to release upon melting of said film, said core member forming a current conducting path of uniform conductivity from terminal to terminal and having surroundings minimizing danger of hot spots therein in the event of a high current value resulting from short-circuit.

'7. A thermal restraining device for electric switches and other devices, comprising a core member having supporting terminals restraining the same against rotation, said core member comprising high resistance material and having intimately bonded thereto an oxide insulating covering extending from terminal to terminal and a second covering of substantially like extent and of material intimately bonding with said oxide covering and affording a bonding surface for solder, said two coverings having a combined thickness of the order of .002 inch, a film of solder bonded to said second covering and an element rotatable about said core member and having a sleeve bonded to said covered core member through the medium of said solder film subject to release upon melting of said film, said core member affording a current conducting path of uniform conductivity from terminal to terminal and having surroundings minimizing danger of hot spots therein when subjected to current flow of the order of a short-circuit.

CLARENCE W. KUHN. 

